Hardware synth
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The document discusses creating a musical instrument called ROMboard using an FPGA (field-programmable gate array). It involves four main parts: 1) an audio CODEC to convert digital signals to audio, 2) a clock divider to generate square waves of the desired musical frequencies, 3) input handling circuitry to map pushbuttons and switches to notes, and 4) integrating the components on the FPGA. The FPGA allows for programming a digital circuit in hardware description language to synthesize music from user input in real-time.
Hardware synth
- 1. Music Synthesis in Hardware Howard Mao April 25, 2013
- 2. ROMboard: An FPGA-based Musical Instrument http://www.youtube.com/watch?v=ap7QOzf1rpI
- 3. What’s an FPGA? A prototyping platform for digital hardware Write a description of a circuit in a hardware description language (HDL) FPGA contains a bunch of configurable logic blocks (CLB) Design tools take HDL code and compiles it to CLB settings for FPGA
- 4. How do we make Romboard?
- 5. Part 1 - Audio CODEC CODEC stands for COder DECoder Turns digital signals into audio signals
- 6. Part 2 - Clock Divider We want to generate a square wave as the audio signal Why square wave? It’s easier to do in hardware Problem: how do we get the right frequency? Hardware clock is at 50 MHz Our music range is 130 Hz (1 octave below middle C) to 523 Hz (2 octaves above middle C). Answer: count up to 50MHz 2f then flip the output
- 7. Part 3 - Input Handling How do we choose notes based on input? 4 Pushbuttons, 17 switches Pushbuttons give 1 when up, 0 when down Switches are 0 when off, 1 when on Use switches to select what notes the pushbuttons map to Pushbuttons + Switches -> Max count for clock divider Use a ROM (Read-Only Memory) to store these values (That’s why it’s called ROMboard)
- 8. Part 4 - Putting it all together